Efficacy Study of Pioglitazone Compared to Glimepiride on Coronary Atherosclerotic Disease Progression in Subjects With Type 2 Diabetes Mellitus

Diabetes is a chronic disease with multiple metabolic defects that result in hyperglycemia arising from inadequate insulin activity. Type 2 diabetes is usually the result of a progression from reduced sensitivity of hepatic and peripheral tissue cells to circulating insulin (ie, insulin resistance) to a progressive inability of the body to produce adequate insulin to overcome insulin resistance (ie, insulin deficiency due to beta-cell insufficiency) resulting in impaired glucose tolerance and ultimately overt diabetes. In the United States, an estimated 21 million people have diabetes, with type 2 diabetes occurring in approximately 90% to 95% of cases. The goal of treating type 2 diabetes is to control blood glucose and thereby prevent long-term complications. Adequate glycemic control is paramount in attempting to avert chronic complications, including blindness; renal dysfunction resulting in dialysis or renal transplantation; neuropathy; non-traumatic amputations; and macrovascular complications, including myocardial ischemia and myocardial infarction, stroke, and peripheral arterial disease. Intensive glucose management in the early stages of diabetes may help forestall such complications. Therapeutic agents have been developed to address each of the major functional metabolic defects associated with type 2 diabetes: decreased beta-cell function, elevated hepatic glucose output, and insulin resistance. Thiazolidinediones increase glucose utilization, decrease gluconeogenesis, and increase glucose disposal by binding to nuclear receptors known as peroxisome proliferator-activated receptors. Thiazolidinediones reduce insulin resistance by enhancing insulin sensitivity in muscle cells, adipose tissue, and hepatic cells (inhibiting hepatic gluconeogenesis), with no direct impact on insulin secretion. Thus, thiazolidinediones improve glycemic control and result in reduced levels of circulating insulin without predisposing patients to hypoglycemia. Peroxisome proliferator-activated receptors are found in tissues important for insulin action, such as adipose tissue, skeletal muscle, and the liver. The greatest concentration of peroxisome proliferator-activated receptors-gamma receptors is in adipose tissue. This study was designed to compare the effects of pioglitazone compared to glimepiride on progression of atherosclerotic disease, as measured by intravascular ultrasound.